Such ventilation systems are used especially in intensive care, and a number of operating parameters, for example, the inspiration pressure, the inspiration time and the expiration time, can be preset by a user, such as an anesthesiologist, in order to set the patient's ventilation in a suitable manner. However, accurate understanding of the patient's physiology is necessary for these settings in order to make it possible to assess the effect of different operating parameters on the patient. The relationships and the dynamic effects are relatively complex, and simple rules of thumb are currently frequently used to make it possible to keep this complexity under control. However, these rules often fail to meet the requirements of the complex physiological processes.
In addition, the problem arises because of the comparatively complex relationships and interactions between individual operating parameters that preset limit values for other operating parameters will change when an operating parameter is varied, so that a user of a ventilation system cannot readily assess the effect of a change made in an operating parameter on limit values for other operating parameters.
It may consequently easily happen that the change made by the user in a first operating parameter causes the limit value for a second operating parameter to change as a result and the preselected setting for this second operating parameter, which should actually remain unchanged, will lead, in an unintended manner, to an actual parameter being higher or lower than the changed limit value. This may possibly remain hidden to the user or was not recognizable at least at the time of selecting the setting for the first operating parameter.
These questionable limit values arise, among other things, from the fact that the patient's lungs are damaged, for example, in case of an excessively high inspiratory pressure or an excessively large tidal volume, i.e., an excessively large breathing air volume per breath. However, since the tidal volume is linked with both the inspiratory pressure and the inspiration time, it may happen that when only the inspiration time is changed, an initially still noncritical inspiratory pressure causes the limit of the tidal volume to be exceeded at the changed inspiration time. The inspiratory pressure set is now all of a sudden above a limit value, even though this was not the case previously.
The use of the prior-art systems known from the state of the art for setting the operating parameters of a ventilation system is comparatively complicated, and it is especially difficult to achieve a setting of the operating parameter that is optimal under boundary conditions without actual values exceeding or dropping below limit values.